NLC-Based Transdermal Patch of Metformin Hydrochloride For 72-Hour Sustained Release

Background: Metformin HCl, the first-line therapy for type 2 diabetes mellitus, with high water solubility and poor lipophilicity, which limits its permeability across the skin barrier. Traditional oral delivery leads to gastrointestinal side effects and requires multiple daily doses due to its short half-life. Nano Lipid Carriers (NLCSs) offer a promising transdermal strategy for sustained and stable delivery of hydrophilic drugs like metformin. Methods: NLCs were formulated using the solvent injection technique, 2² full factorial design was employed to optimize the formulation, focusing on variables such as solid lipid ratio and concentration of surfactant. The optimized NLCs were incorporated into a polymeric transdermal patch composed of HPMC and PVP, with Dibutyl phthalate as plasticizer. The formulations were evaluated for particle size, zeta potential and entrapment efficiency. The prepared patches were subjected to physicochemical evaluation (thickness, folding endurance, surface pH, drug content, and moisture content) and tested for in vitro drug release using Franz diffusion cells. Results: The optimized NLC achieved a particle size of approximately 361.8 nm and an entrapment efficiency of 89.8%,indicating suitability for topical application. The NLC-loaded patches showed smooth, flexible surfaces with acceptable mechanical properties. In vitro studies demonstrated sustained release of Metformin HCl over 72 hours, with improved permeation compared to conventional patches.Conclusion: NLC-based transdermal patches of Metformin HCl present a viable approach to enhance bioavailability and provide sustained antihyperglycemic action, potentially improving therapeutic compliance in diabetic patients.